In a previous FiveBooks interview I asked Justice Stephen Breyer what members of the US Supreme Court do. He replied, “Our job, the nine of us, is basically to create a uniform rule of law by ironing out differences.”

They serve as the final interpreters of what the US constitution says and means in any situation. And they sit as the final arbiters of what a statute says or means in any given situation. [Retired] Justice David Souter gave a really powerful speech at Harvard where he talked about how often those two things are in tension.

We pretend that there is one easy answer for every question that comes to court and we forget that almost every case that gets to the Supreme Court is a close case. In almost every case there are two competing answers or constitutional values that the justices have to chose between. Whether they use ouija boards to channel the framers or just look inside their hearts, what they do is the opposite of calling balls and strikes.

If you had to write a help-wanted ad for the position of Supreme Court justice, what would you include in the job description?

It would start with: Those who went to Harvard or Yale Law School need not apply. Every sitting justice went to Harvard or Yale. That tells you something about the very narrow bandwidth from which the members of the court are coming. And it’s not just the law school they went to – more and more nominees worked for the executive branch. Everybody who is on the court right now, with the exception of Justice Elena Kagan, came off the bench. Justice Ruth Bader Ginsburg is the only one on the court who was a civil rights attorney. Back in the day, we used to have people like Sandra Day O’Connor and Earl Warren, who served in elected office. Now none of those people could get confirmed. There is a narrowing in the backgrounds of nominees when what we need is diversity – diversity of voice, of belief, of career and of experience.

Beyond that, I think empathy got a bad rap. During Sonia Sotomayor’s hearings, the suggestion that Barack Obama should select someone who exhibits empathy was shot down as an unspeakable idea. Empathy shouldn’t be confused with sympathy and it shouldn’t be confused with bias. It means the ability to walk a mile in somebody else’s shoes. That may be the single most important quality going into a court where once you are seated you never walk anywhere in anyone else’s shoes. You are exposed to an extremely narrow range of people, you just think and write.

What do you learn from sitting in on oral arguments of the court that you can’t learn from studying case law?

The first thing you learn is that most justices don’t come to argument with an easy answer in their pocket. They don’t use it as a way to show off, they are incredibly well prepared. The problem with the way the court lets itself be covered in the US is this. If you only hear about a decision when it comes out those last two weeks in June [at the end of the court’s term], it pops out like a jack-in-the-box. It’s very easy to see the court as an ends-driven institution, because all you see is the end product, not the briefs, not the arguments and not the full decision or dissents. So for me the virtue of sitting in on oral argument is that you see the process. If each advocate does their job well, you see that these are extremely hard, nuanced questions, and that the answers aren’t as easy as they might seem if you only read about the decisions.

You also get to see the court work as a team. If you read about a five-four decision it’s easy to caricature the court as polarised, liberal-conservative, good guys-bad guys – depending on your politics. Watching oral argument, it’s clear that there aren’t two teams. Most decisions don’t come out five-four. Liberals side with conservatives on most cases and vice versa. The end product in no way tells the whole story.